WebDAV improvements: flush fix, RwLock recovery, expired lock cleanup, atomic set_times

P0 fixes:
- flush(): add flushed flag, proper error logging, Drop warning for data loss
- props_data RwLock: replace unwrap() with try_read/try_write recovery
- PersistedLs: add is_expired() + cleanup_expired_locks() helper

P1 improvements:
- Props persistence via VFS (load_props/save_props/patch_props)
- COPY/MOVE sync dead props (copy on COPY, move key on rename)
- Atomic set_atime/set_mtime via filetime crate (no race condition)

New files:
- webdav_locks.rs: PersistedLs with lock persistence + expiry cleanup

Tests: 288 passed, 0 failed

markbase-core/src/webdav_version.rs

@@ -28,11 +28,31 @@ pub struct VersionHistory {
 pub struct WebDavVersioning {
     db: Arc<RwLock<HashMap<String, Vec<u8>>>>,
     version_storage: PathBuf,
+    index_path: PathBuf,
 }
 
 impl WebDavVersioning {
-    pub fn new(db: Arc<RwLock<HashMap<String, Vec<u8>>>>, version_storage: PathBuf) -> Self {
-        Self { db, version_storage }
+    pub fn new(version_storage: PathBuf) -> Self {
+        let index_path = version_storage.join("version_index.json");
+        let db = Arc::new(RwLock::new(HashMap::new()));
+
+        // Load persisted index from disk
+        if index_path.exists() {
+            if let Ok(json) = std::fs::read_to_string(&index_path) {
+                if let Ok(map) = serde_json::from_str::<HashMap<String, Vec<u8>>>(&json) {
+                    *db.write().unwrap() = map;
+                }
+            }
+        }
+
+        Self { db, version_storage, index_path }
+    }
+
+    fn save_index(&self) -> Result<(), VersionError> {
+        let db = self.db.read().unwrap();
+        let json = serde_json::to_string(&*db)?;
+        std::fs::write(&self.index_path, json)?;
+        Ok(())
     }
 
     pub fn create_version(
@@ -71,9 +91,10 @@ impl WebDavVersioning {
         let value = serde_json::to_vec(&version_info)?;
         self.db.write().unwrap().insert(key, value);
 
-        let history_key = Self::history_key(file_path);
         self.update_version_history(file_path, &version_id)?;
 
+        self.save_index()?;
+
         Ok(version_info)
     }
 
@@ -144,6 +165,8 @@ impl WebDavVersioning {
 
         self.update_version_history(file_path, &new_version_id)?;
 
+        self.save_index()?;
+
         Ok(new_version_info)
     }
 
@@ -165,6 +188,8 @@ impl WebDavVersioning {
         let current = self.get_current_version(file_path)?;
         self.update_version_history(file_path, &current.version_id)?;
 
+        self.save_index()?;
+
         Ok(())
     }
 
@@ -249,14 +274,12 @@ impl From<serde_json::Error> for VersionError {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use std::sync::Arc;
     use tempfile::TempDir;
 
     fn setup_versioning() -> (WebDavVersioning, TempDir) {
         let version_dir = TempDir::new().unwrap();
 
-        let db = Arc::new(RwLock::new(HashMap::new()));
-        let versioning = WebDavVersioning::new(db, version_dir.path().to_path_buf());
+        let versioning = WebDavVersioning::new(version_dir.path().to_path_buf());
 
         (versioning, version_dir)
     }